Compute each of the following.
((a)) (5x2+3x−4)+(4x2−x+9) in Z12[x]
((b)) (5x2+3x−4)(4x2−x+9) in Z12[x]
((c)) (7x3+3x2−x)+(6x2−8x+4) in Z9[x]
((d)) (3x2+2x−4)+(4x2+2) in Z5[x]
((e)) (3x2+2x−4)(4x2+2) in Z5[x]
((f)) (5x2+3x−2)2 in Z12[x]
Hint. (a) 9x2+2x+5; (b) 8x4+7x3+2x2+7x.